As more becomes known about the devastating Arizona wildfire that killed 19 members of a hotshot team, broader questions are being raised, including roles of residential development and climate change.

Photos of the 19 fallen Granite Mountain Hotshot firefighters and the lone survivor of the fatal blaze hang outside a fire station in Prescott, Ariz. Nearly a week after 19 Granite Mountain Hotshot firefighters died battling a blaze near Yarnell, Ariz., mourners continue to visit and grow the memorial.

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Julie Jacobson/AP

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Ashland, Oregon — As more becomes known about the devastating Arizona wildfire that killed 19 members of a “hotshot” team, broader questions are being raised:

How to address the spread of residential expansion into the “wildland-urban interface” where homes quickly become fuel – particularly in areas of the mountain West where zoning and other government regulations are very unpopular.

And to what extent have changing climate patterns become a cause of such blazes at a time when the US Forest Service is having to spend increasing amounts of its budget on firefighting?

Based on officials’ initial analysis and a map of how the tragedy unfolded compiled by the Associated Press, “an erratic wildfire driven by ferocious and shifting winds curled around the location of a team of Arizona Hotshot firefighters, cutting off their access to a safety zone and creating a death trap that quickly consumed them,” the AP reports.

“In just one hour, between 4 and 5 p.m., winds shifted 180 degrees and nearly doubled in strength to 41 mph. Photographic evidence suggests the fire’s enormous mushroom cloud collapsed on itself, sending smoke and heat into canyons,” The Arizona Republic reported Saturday. “The phenomenon is similar to a microburst – hot air from the fire rises and is rapidly cooled when it meets the monsoon front. As the cooled air becomes heavier, it rapidly falls to the ground, creating highly destructive winds that feed the fire and spread it in all directions.”

The 20th member of the hotshot crew – 21-year-old Brendan McDonough – had been posted as a lookout on a nearby ridge. He radioed a warning about shifting winds, and when his own position became perilous he headed to safety.

“He did exactly what he was supposed to do,” Prescott Fire Department spokesman Wade Ward has been quoted as saying.

But in the end it was too late for his comrades. Surrounded by fire, they deployed tent-like individual shelters in hopes that they could survive as the blaze roared over them, but that last-ditch protection measure proved inadequate to the size and intensity of the fire and all perished.

"Apparently their escape route was inadequate," Carl Seielstad, an associate research professor and fire and fuels program manager at the University of Montana's National Center for Landscape Fire Analysis, told the AP. "All of these fatalities associated with fire shelter deployments have commonalities that relate to sudden and unexpected changes in fire behavior, that firefighters were in a compromising position and failed to recognize the danger they were in until it was too late,”

“After the fact when we look back, we always think, 'They should have expected this,'" said Mr. Seielstad, a former smokejumper and hotshot. "These investigations are always awkward for other firefighters because they sort of imply that mistakes were made, although maybe mistakes were made."

Detailed investigations are underway now, and official reports will take months to compile. But some local residents say the nearby terrain – giant boulders, thick stands of scrub oak and manzanita – made it particularly difficult to fight fires and to escape quickly if necessary.

"Knowing the area, you couldn't scramble out of there if you had to," local school board member Eric Lawton told the AP. "I don't care about [having a] special meteorologist on site or any of that, they had no chance."

Since 1991, the portion of the US Forest Service budget spent fighting wildland fires has gone from about 13 percent to more than 40 percent – much of it in the wildland-urban interface where homebuilding has pushed into what once was wilderness.

Meanwhile, officials see a direct connection with climate change.

“On average, wildfires burn twice as many acres each year as compared to 40 years ago. Last year, the fires were massive in size, coinciding with increased temperatures and early snow melt in the West,” US Forest Service Chief Tom Tidwell told the Senate Energy and Natural Resources Committee in testimony last month. “The largest issue we now face is how to adapt our management to anticipate climate change impacts and to mitigate their potential effects.”

By Friday, the fire near the small community of Yarnell, Arizona, had been 90 percent contained. But not before destroying more than 100 homes and burning about 13 square miles.